Manhattan is an island thanks to three so-called ‘rivers,’ even though two of them, the Harlem and the East, are actually tidal straits, and the third, the Hudson, is what geologists call a ‘drowned river’—in other words, pretty much a fjord. Not surprisingly, figuring out what the tide is doing in New York Harbor can be a challenge, especially when you take into account the phenomenon known as tidal current lag.

In most other places in the world, high tide marks the moment when the current switches from flood (rising or inbound) to ebb (falling or outbound). Knowing what the tide is going to do is a simple matter of reading the tide tables; the tide comes in until high tide, then goes out until low tide. Not so in New York Harbor. Depending on the location, the lag between high or low water and the beginning of the flood or ebb can be as much as three hours, which is nearly half the tide cycle (high and low tides are typically six and a half hours apart).

One traditional source of information on tidal currents is the series of charts (link to our copies) in the famous yellow Eldridge Tide and Pilot book. The one pictured above, for instance, shows the harbor currents four hours after high water at the Battery. Kind of hard to read, and lots of page-flipping when planning a trip.

Several years ago, Don Betts, a Brooklyn boatbuilder, rower and sailor, came up with an ingenious and graphically simple way to gauge the tidal current lag. It consisted of three concentric rings, one for each of the Harbor’s ‘rivers,’ and in the center a clock face which one could spin so as to align the predicted time of high tide on the vertical axis at the top of the dial. Initially he made them in paper, copied and laminated them, and then handed them out to friends and coxswains, or skippers, at the community rowing group Floating the Apple.

Later he made some bigger versions in painted plywood. The one pictured below is at the Village Community Boathouse on Pier 40. It’s set for a high tide time of 10:15 and shows the Hudson River flood running until about 1. We use it on a daily basis, and it’s really indispensable when planning longer voyages to the East River or all the way around the island.

What we propose for the East River Waterfront Esplanade and Piers Project is to install at least one large, durable version of Don’s tide wheel as both a work of art and an interactive, educational tool that passersby and, eventually, human-powered boaters could use to gain a better understanding of the tides and tidal currents in the harbor. It’s our belief that this simple, sundial-like device would serve two constituencies who have, until now, been unable to find much common ground: those who are unfamiliar with, and sometimes fearful of, the harbor and its workings, and those keen to venture forth upon its waters.

Our preferred installation site would be on or adjacent to the beach under the Manhattan end of the Brooklyn Bridge, since that is one site in the project where the height of the tide is immediately apparent, and also the place where human-powered vessels are most likely to launch someday. Below is a digital rendition of how the tide wheel might look at that site if it were attached directly to the esplanade railing.

What we propose for the East River Waterfront Esplanade and Piers Project is to install at least one large, durable version of Don’s tide wheel as both a work of art and an interactive, educational tool that passersby and, eventually, human-powered boaters could use to gain a better understanding of the tides and tidal currents in the harbor. It’s our belief that this simple, sundial-like device would serve two constituencies who have, until now, been unable to find much common ground: those who are unfamiliar with, and sometimes fearful of, the harbor and its workings, and those keen to venture forth upon its waters.

Our preferred installation site would be on or adjacent to the beach under the Manhattan end of the Brooklyn Bridge, since that is one site in the project where the height of the tide is immediately apparent, and also the place where human-powered vessels are most likely to launch someday. Below is a digital rendition of how the tide wheel might look at that site if it were attached directly to the esplanade railing.

The wheel might at first strike un-nautical types as overly enigmatic, a cipher. But we feel that a bit of mystery might actually add to its allure and cause people to draw closer, whereupon more information could be made available. One potential component of the installation we’d like to see, but have not depicted here, is a weatherproof ‘book’ of laminated sheets with some explanatory paragraphs as well as a set of tables listing daily high tide times for the year.

Another and perhaps more appealing idea than attaching the wheel to the railing might be to mount it on a pole sunk directly into the beach itself. We feel the iconic shape of the disc on the pole would function as a sort of visual ‘stop sign’ for would-be users of the harbor, encouraging them to think about their float plan and what the tidal currents are doing before entering the water. Such a configuation might look something like this: